$\left(-10x - 10\right)^2 = \ ?$
Explanation: $= \left(-10x - 10\right)\left(-10x - 10\right)$ $= -10x \cdot \left(-10x - 10\right) - 10 \cdot \left(-10x - 10\right)$ $= \left( -10x \cdot -10x \right) + \left( -10x \cdot -10 \right) + \left( -10 \cdot -10x \right) + \left( -10 \cdot -10 \right)$ $= 100x^2 + \left( -10x \cdot -10 \right) + \left( -10 \cdot -10x \right) + \left( -10 \cdot -10 \right)$ $= 100x^2 + \left( 100x + 100x \right) + \left( -10 \cdot -10 \right)$ $= 100x^2 + 200x + \left( -10 \cdot -10 \right)$ $= 100x^2 + 200x + 100$